Theorem sbhypf 2788

Description: Introduce an explicit substitution into an implicit substitution hypothesis. See also csbhypf . (Contributed by Raph Levien, 10-Apr-2004.)

Hypotheses

Ref	Expression
sbhypf.1	|- F/ x ps
sbhypf.2	|- ( x = A -> ( ph <-> ps ) )

Assertion

Ref	Expression
sbhypf	|- ( y = A -> ( [ y / x ] ph <-> ps ) )

Distinct variable groups:   x, A   x, y

Allowed substitution hints:   ph( x, y)   ps( x, y)   A( y)

Proof of Theorem sbhypf

Step	Hyp	Ref	Expression
1		vex 2742	. . 3 |- y e. _V
2		eqeq1 2184	. . 3 |- ( x = y -> ( x = A <-> y = A ) )
3	1, 2	ceqsexv 2778	. 2 |- ( E. x ( x = y /\ x = A ) <-> y = A )
4		nfs1v 1939	. . . 4 |- F/ x [ y / x ] ph
5		sbhypf.1	. . . 4 |- F/ x ps
6	4, 5	nfbi 1589	. . 3 |- F/ x ( [ y / x ] ph <-> ps )
7		sbequ12 1771	. . . . 5 |- ( x = y -> ( ph <-> [ y / x ] ph ) )
8	7	bicomd 141	. . . 4 |- ( x = y -> ( [ y / x ] ph <-> ph ) )
9		sbhypf.2	. . . 4 |- ( x = A -> ( ph <-> ps ) )
10	8, 9	sylan9bb 462	. . 3 |- ( ( x = y /\ x = A ) -> ( [ y / x ] ph <-> ps ) )
11	6, 10	exlimi 1594	. 2 |- ( E. x ( x = y /\ x = A ) -> ( [ y / x ] ph <-> ps ) )
12	3, 11	sylbir 135	1 |- ( y = A -> ( [ y / x ] ph <-> ps ) )

Syntax hints:   -> wi 4   /\ wa 104   <-> wb 105   = wceq 1353   F/wnf 1460   E.wex 1492   [wsb 1762

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-5 1447  ax-gen 1449  ax-ie1 1493  ax-ie2 1494  ax-8 1504  ax-11 1506  ax-4 1510  ax-17 1526  ax-i9 1530  ax-ial 1534  ax-i5r 1535  ax-ext 2159

This theorem depends on definitions:  df-bi 117  df-tru 1356  df-nf 1461  df-sb 1763  df-clab 2164  df-cleq 2170  df-clel 2173  df-v 2741

This theorem is referenced by:  mob2  2919  cbvmptf  4099  tfisi  4588  ralxpf  4775  rexxpf  4776  nn0ind-raph  9372